TY - JOUR
T1 - The role of aluminium and titanium in the point defects of gamma irradiated natural quartz
AU - Sawakuchi, G. O.
AU - Okuno, E.
PY - 2005
Y1 - 2005
N2 - In this work, the origin of the smoky colour acquired by quartz when exposed to extremely high doses (20 kGy) of ionising radiation is studied. Five paramagnetic centres were detected in the electron paramagnetic resonance (EPR) spectrum of irradiated quartz: [AlO4]0, [TiO 4-/Li+]A0, [GeO4-/Na +]A0, [GeO4-/Li+] C0, and E'1. Optical absorption revealed a complex spectrum with superposition of bands. With the technique of thermoluminescence, at least three peaks at around 180, 260 and 320°C were detected. The peak at around 180°C has maximum emission at 470 nm and the peaks at around 260 and 320°C have maximum emissions at 450 nm. Through correlations between the obtained results with these techniques, it was possible to confirm previous results from the literature, i.e., that the smoky colour of quartz is strongly related to the centre [AlO4]0. Besides, it was verified an excellent correlation between the thermal decay of [AlO4]0 and [TiO4-/Li+] A0, suggesting that at a temperature around 200°C the Li leaves the Ti centre and recombines with the aluminium centre destroying the smoky colour of irradiated quartz. On the other hand and differently from the literature this process does not correlate to any of the thermoluminescence peaks.
AB - In this work, the origin of the smoky colour acquired by quartz when exposed to extremely high doses (20 kGy) of ionising radiation is studied. Five paramagnetic centres were detected in the electron paramagnetic resonance (EPR) spectrum of irradiated quartz: [AlO4]0, [TiO 4-/Li+]A0, [GeO4-/Na +]A0, [GeO4-/Li+] C0, and E'1. Optical absorption revealed a complex spectrum with superposition of bands. With the technique of thermoluminescence, at least three peaks at around 180, 260 and 320°C were detected. The peak at around 180°C has maximum emission at 470 nm and the peaks at around 260 and 320°C have maximum emissions at 450 nm. Through correlations between the obtained results with these techniques, it was possible to confirm previous results from the literature, i.e., that the smoky colour of quartz is strongly related to the centre [AlO4]0. Besides, it was verified an excellent correlation between the thermal decay of [AlO4]0 and [TiO4-/Li+] A0, suggesting that at a temperature around 200°C the Li leaves the Ti centre and recombines with the aluminium centre destroying the smoky colour of irradiated quartz. On the other hand and differently from the literature this process does not correlate to any of the thermoluminescence peaks.
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U2 - 10.1002/pssc.200460241
DO - 10.1002/pssc.200460241
M3 - Article
AN - SCOPUS:27344441802
SN - 1610-1634
VL - 2
SP - 588
EP - 591
JO - Physica Status Solidi C: Conferences
JF - Physica Status Solidi C: Conferences
IS - 1
ER -